Joshua 20:1-4

Then the LORD spoke to Joshua, “Tell the Israelites: Select your cities of refuge, as I instructed you through Moses, so that a person who kills someone unintentionally or accidentally may flee there. These will be your refuge from the avenger of blood. When someone flees to one of these cities, stands at the entrance of the city gate, and states his case before the elders of that city, they are to bring him into the city and give him a place to live among them.